Motor Oil - Fossil or Synthetic

John Appleton

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someone floated the idea that high quality oils caused Harley big-end rollers to "skid"

Tom, just a point to remember here is that ALL roller bearings skid to a greater or lesser degree . It is further around the circumferance of an outer track than it is around the inner track, and the fact that rollers are not positively driven encourages skid. This is in effect a wiping motion making the use of ZDPP desireable.
John
 
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ET43

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Just had a squirt around the internet, and John Appleton's words are very informative, confirmed by other information found at www.smartsynthetics.com and at this magazine, Real Classics, Techniques - The Oil Truth. Not that I doubted you John, grovel, grovel. Folks who run wet clutches might want to read both of these articles. One is American and the other from the U.K. An enlightened ET43
 

Rob T

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I use Morris 20/50 Magnol in my Comet. I have done for the 5000 plus miles since rebuild and inside the motor is looking like new. More important is to get the oil warm and remember to keep it clean. Remember what your mum told you as a child about cleanliness!
 

Len Matthews

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Quite agree Rob. I believe that Magnol 20/50 has been rebranded as Golden Film but it's good stuff! Problem is it might be difficult to obtain overseas so if your bike is using a fair bit of oil, best to take some with you when touring outside the UK.
 

mr.hutch

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Just to add my ten pennyworth folks,
I have been using Morris Golden Film SAE50 in the summer and SAE30 for the winter without any problems.
Also, not only can I walk to my local agent just up the road, who's main interest is vintage tractors etc. and worth a visit in its own right, but it's a lot cheaper than the GTX 20/50 I used to use.
Someone told me a while back that the firm of Morris were blenders of oil rather than producing it from scatch, which is interesting. They are certainly well known for quality in the world of steam heritage and preserved railways, for lubricating and heavy steam oil among others.
I shall continue to use their product, for the foreseeble future.
 
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vibrac

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Since it looks like you all need to carry oil with you now, thats put to rest the last objection I had to my choice of oil for the last 20 years road and track: CASTOR OIL for my Vincent racers and Alphabet twin. I do use Halfords Classic in the single but the insides are a lot more dirty and I have to wear rubber gloves when stripping components. Occasionally it seems even a non tree hugger like me likes organic products!
 

Old Bill

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Gentlemen, some thoughts, oil and engine technology have advanced in leaps and bounds since Vincent ceased production. Engines have closer finished tolerances than ever before, Lubricants are a complex mixture defined by viscosities and formulation. Straight Oils have a high detergent action to suspend combustion debris etc which makes regular changes essential, invalueable in power units devoid of proper filtration. The Vincent Engines of course have good filtration so modern non synthetic multigrades are probably better suited to this application than Straight oils, the key is climatic conditions prevelent to machine operation coupled with products availability and possibly cost. As I said, just a thought.............................
 

Tnecniv Edipar

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Just for the record the majority of Automotive lubricating oil manufacturers are blenders of oils, they obtain their ingredients from the oil majors or large wholesalers. It's only the majors that produce their own lube oils from scratch, like Shell etc, which is not to say they produce the best because of that. THE most important ingredient is the base stock, that it the foundation of the oil, the best quality base stocks are expensive so you get what you pay for. Then come the additive packages, again the best are expensive. These days it's the additives that determine the application of a given oil, the applications can be very specific down to certain models of car in a range.
In the case of Vincents it's the viscosity that's most important and most make the mistake of using too high a grade, the operating temperature of Vin motors is very low in standard form, so as was mentioned above, 20 should be considered the limit in a temperate climate, 5/30 would be a good multigrade choice. Assessing the viscosity as it appears from the can at ambient temperature is a pointless exercise, engine oil is complex chemistry and difficult to analyse without a lab. Shear stability is extremely good with all quality oil these days.

Personally I would not use an expensive synth oil in a Vin, a high quality, general purpose mineral engine oil is more than adequate. My own choice is Morris for classic machines.
 
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